diff --git a/src/plugins/platforms/windows/qwindowssystemtrayicon.cpp b/src/plugins/platforms/windows/qwindowssystemtrayicon.cpp
index 22cdefbbbc..ab830e1461 100644
--- a/src/plugins/platforms/windows/qwindowssystemtrayicon.cpp
+++ b/src/plugins/platforms/windows/qwindowssystemtrayicon.cpp
@@ -57,6 +57,7 @@
 #include "qwindowsmenu.h"
 #include "qwindowsscreen.h"
 
+#include <QtGui/qguiapplication.h>
 #include <QtGui/qpixmap.h>
 #include <QtCore/qdebug.h>
 #include <QtCore/qrect.h>
@@ -135,6 +136,9 @@ static int indexOfHwnd(HWND hwnd)
 extern "C" LRESULT QT_WIN_CALLBACK qWindowsTrayIconWndProc(HWND hwnd, UINT message,
                                                            WPARAM wParam, LPARAM lParam)
 {
+    // QTBUG-79248: Trigger screen update if there are no other windows.
+    if (message == WM_DPICHANGED && QGuiApplication::topLevelWindows().isEmpty())
+        QWindowsContext::instance()->screenManager().handleScreenChanges();
     if (message == MYWM_TASKBARCREATED || message == MYWM_NOTIFYICON
         || message == WM_INITMENU || message == WM_INITMENUPOPUP
         || message == WM_CLOSE || message == WM_COMMAND) {